[Gate-users] Why the dose of water phantom from Yttrium-90 is nearly double the original estimate?

李昕迪 Lee, Sin-di mcdlee at gmail.com
Tue Jul 10 06:15:32 CEST 2018

Hello GATErs:

 I made a simulation with a 1-kg water phantom filled with 1 GBq
Yttrium-90 and recorded the dose of the phantom with a 10*10*10

 The code Yttrium-90 source was as following:
/gate/source/Y90/gps/particle ion
/gate/source/Y90/gps/ion 39 90 0 0
/gate/source/Y90/setForcedUnstableFlag true
/gate/source/Y90/setActivity 1 GBq
/gate/source/Y90/gps/angtype iso

 I used the method of setTotalNumberOfPrimaries.

/gate/application/setTotalNumberOfPrimaries 10000

 Because the mean energy of the beta ray of Yttrium-90 is 0.9267 MeV,
the estimated dose is 1.4827E-9 Gy. However, the result of simulation
is 3.0259E-9.

 I made another simulation with more primary particles up to 1E6, and
the result is the same.

 Does somebody have a clue?

The full code was here.

 Thanks a lot.


Sin-Di Lee

李昕迪 Lee, Sin-di | http://www.mcdlee.tw

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